from jinja2 import Environmentdef environment(**options):    env = Environment(**options)    # 2.将自定义的过滤器添加到 环境中    env.filters['do_listreverse'] = do_listreverse    return env# 1.自定义过滤器def do_listreverse(li):    if li == "B":        return "哈哈"    else:        return '不成立'